JP6474635B2 - Method for producing urethane / (meth) acrylic composite resin particles - Google Patents

Description

  The present invention relates to a method for producing particulate urethane / (meth) acrylic composite resin particles.

  As a production method for obtaining a urethane / (meth) acrylic composite resin (hereinafter sometimes abbreviated as “U / A resin”) as an aqueous dispersion, a production method as shown in Patent Document 1 is generally used. Known. That is, an isocyanate, a diol, and / or a polyol (hereinafter collectively referred to as a “polyol compound”) are dissolved in a (meth) acrylic monomer to form a urethane polymer in the solution. Next, the phase is changed by adding water (as the urethane polymer solution of the (meth) acrylic monomer is finely dispersed in the aqueous medium), and finally the emulsion polymerization of the (meth) acrylic monomer is performed. Is the method.

JP 11-14149 A

  By the way, the U / A resin obtained by a conventionally known polymerization method such as Patent Document 1 described above is fine particles of submicron level of about several tens nm to several hundreds nm. For this reason, in order to process this, it was common to carry out without separating U / A resin from the water which is a medium by the coating method etc. which are usually used for emulsion processing.

However, in order to transport the U / A resin obtained by this method, it is necessary to transport a dispersion (emulsion) of U / A resin accompanied by a large amount of water. It was hard to say.
In order to avoid this, the U / A resin may be dried by using a special drying method such as a spray drying method to form solid particles. Depending on the composition of the resin and the like, there is a problem that heat fusion or the like occurs during spray drying, making it difficult to adjust the particle size or sticking to the inner wall of the dryer.

  Therefore, the present invention obtains U / A resin particles having a larger particle size, thereby reducing energy consumption for separating water and resin, facilitating separation from water, and improving transportation efficiency. It aims at improving the handleability of the resin.

The gist of the present invention resides in the following [1] to [9].
[1] The component (A) which is a urethane polymer and the component (B) which is a (meth) acrylic monomer are added and dispersed in an aqueous medium containing the component (C) which is a dispersion stabilizer. A method for producing urethane / (meth) acrylic composite resin particles, wherein the component (B) is polymerized using the component (D) which is a polymerization initiator.
[2] The urethane / containing composition according to [1], wherein a mixture obtained by previously mixing the component (A) and the component (B) is added and dispersed in an aqueous medium containing the component (C). A method for producing (meth) acrylic composite resin particles.

[3] A mixture obtained by previously mixing the component (A) and the component (B) reacts with a carboxyl group-containing diol and a polyvalent isocyanate compound in the presence of the component (B), and ) The method for producing urethane / (meth) acrylic composite resin particles according to [2], which is obtained by generating a component.
[4] Production of urethane / (meth) acrylic composite resin particles according to [3], wherein at least a part of the carboxyl group of component (A) is neutralized with a basic compound Method.

[5] The weight ratio of the component (A) to the component (B) is (A) / (B) = 80/20 to 20/80. The manufacturing method of the urethane / (meth) acrylic-type composite resin particle of any one.
[6] The method for producing urethane / (meth) acrylic composite resin particles according to any one of [1] to [5], wherein the component (C) is partially saponified polyvinyl acetate. .

[7] The urethane / (meta) according to any one of [1] to [6], wherein the urethane / (meth) acrylic composite resin particles have a particle size of 5 to 250 μm. ) A method for producing acrylic composite resin particles.
[8] Urethane / (meth) acrylic composite resin particles having an average particle diameter of 5 to 250 μm.

  Since the particle size of the U / A resin obtained by the production method of the present invention is, for example, a micron level of about 5 to 250 μm, it is about 1000 times larger than the particles obtained by the conventional emulsion polymerization method. For this reason, as a method of separating from water, it is possible to use a simple method that requires little energy, such as filtration, the U / A resin can be efficiently separated and obtained, and is dried by a conventional method. It is also possible. For this reason, the obtained urethane / (meth) acrylic composite resin particles can be transported in the form of particles, and transport can be made efficient.

Optical micrograph of fine particles obtained in Example 1 Optical micrograph of fine particles obtained in Example 2

Hereinafter, the present invention will be described in detail.
This invention starts polymerization of a mixture of a urethane polymer (component (A)) and a (meth) acrylic monomer (component (B)) in an aqueous medium containing a dispersion stabilizer (component (C)). This is a method for producing urethane / (meth) acrylic composite resin (U / A resin) particles by polymerizing the component (B) using an agent (component (D)).

[1. Urethane polymer (component (A))]
The urethane polymer as the component (A) is a polymer obtained by urethanizing a polyvalent isocyanate compound and a polyol compound.

  The polyvalent isocyanate compound refers to a compound having at least two isocyanate groups in one molecule. Specific examples thereof include tolylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, and mixtures thereof. Can be given.

The polyol compound is a compound having at least two hydroxyl groups in one molecule.
Specific examples thereof include ethylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1, Relatively low molecular weight polyols such as 6-hexanediol, neopentyl glycol, diethylene glycol, trimethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, cyclohexane dimethanol, methylpentanediol adipate, or A polyester polymer obtained by polycondensation of at least one of these with at least one dicarboxylic acid such as adipic acid, sebacic acid, itaconic acid, (anhydrous) maleic acid, (anhydrous) phthalic acid, terephthalic acid, and isophthalic acid. Polyols such as all, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polybutadiene polyol, hydrogenated polybutadiene polyol, polyalkylene glycol, polycaprolactone polyol, polycarbonate polyol, polyacrylate polyol, and these polyols And polyether polyols obtained by adding propylene oxide to the above.
These polyol compounds may use only 1 type and may use multiple types.

  Among these polyol compounds, the above-mentioned polycarbonate diol, polyester-based diol or polyol is preferable in that it is less sticky (tackiness) when formed into particles.

  When a carboxyl group-containing diol is used as the diol compound, the resulting component (A) (urethane polymer) stabilizes the aqueous dispersion due to the presence of the carboxyl group, and also stabilizes dispersion during suspension polymerization described below. It is preferable because it can also be obtained.

When it is desired to obtain the component (A) as an aqueous dispersion, the mixing ratio of the polyvalent isocyanate compound and the diol compound is polyvalent isocyanate compound / diol compound (equivalent ratio) = 1.2 / 1.0 or more, 2.0 / 1.0 or less is preferable.
When the mixing ratio is less than 1.2 / 1.0, the viscosity of the urethane prepolymer to be produced is high, and the dispersibility in an aqueous medium is lowered during suspension polymerization, which will be described later, causing aggregation and coarse particles. Sometimes. On the other hand, if the mixing ratio is greater than 2.0 / 1.0, the amount of unreacted polyvalent isocyanate increases, and the dispersion state deteriorates due to aggregation during foaming of the aqueous medium or foaming. is there.
The lower limit of the mixing ratio is more preferably 1.4 / 1.0, and the upper limit thereof is more preferably 1.9 / 1.0.

  The reaction temperature and reaction time of the urethanization reaction may be the same conditions as those usually used in the production of urethane polymers. For example, the reaction temperature is 50 to 120 ° C., preferably 70 to 100 ° C., and the reaction time is 0. 5 to 15 hours, preferably 2 to 7 hours, more preferably 3 to 5 hours.

  When the carboxyl group-containing diol is used, the ratio of the carboxyl group-containing diol to the total diol compound is preferably 30% by weight or less, and preferably 20% by weight or less. If it is larger than 30% by weight, it may be unfavorable in that it easily dissolves in water. On the other hand, the lower limit of the use ratio is preferably 0.5% by weight, and preferably 1.0% by weight. If it is less than 0.5% by weight, it may be difficult to form fine particles having a desired particle diameter, which is not preferable.

When a carboxyl group-containing diol is used as a part of the diol compound, that is, when a carboxyl group is contained in the component (A), if necessary, at least a part of the carboxyl group of the component (A) is basic. By neutralizing with a compound, the dispersibility of the particles may be improved.
Examples of this basic compound include sodium hydroxide, potassium hydroxide, monomethylamine, dimethylamine, monoethylamine, diethylamine, ammonia and the like.

[2. (Meth) acrylic monomer (component (B))]
The component (B) is a (meth) acrylic monomer and is a monofunctional (meth) acrylic monomer having one double bond or a polyfunctional (meth) acrylic monomer having a plurality of double bonds. Monomers are included. Moreover, when this (B) component has a functional group which can couple | bond with urethane polymer ((A) component) like a hydroxyl group, for example, (A) component and (B) component will be more closely compounded. Is preferable. Such a polymerizable monomer having a functional group capable of binding to the urethane polymer (component (A)) is referred to as a “urethane-binding polymerizable monomer”.
In this specification, “(meth) acryl” means “acryl or methacryl”.

  Examples of the monofunctional (meth) acrylic monomer include (meth) acrylic acid esters such as (meth) acrylic acid alkyl ester and (meth) acrylic acid alkoxyalkyl ester.

  Specific examples of the (meth) acrylic acid alkyl ester include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, and 2-ethylhexyl (meth) acrylate. Cyclohexyl (meth) acrylate, benzyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, isobornyl (meth) acrylate, and the like.

  Specific examples of the alkoxyalkyl ester (meth) acrylate include 2-methoxyethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, 2-butoxyethyl (meth) acrylate, and the like. .

  Specific examples of the polyfunctional (meth) acrylic monomer include bifunctional (meth) acrylic monomers such as 1,6-hexanediol di (meth) acrylate and 1,9-nonanediol di (meth) acrylate. Monofunctional or trifunctional (meth) acrylates such as trimethylolpropane tri (meth) acrylate and dipentaerythritol hexa (meth) acrylate can be exemplified, and as the polyfunctional urethane-binding polymerizable monomer A trisacrylic acid = hydroxyethyl lysine tri (methylene) etc. can be illustrated.

Examples of the urethane-bonding polymerizable monomer include hydroxyl group-containing (meth) acrylic monomers such as hydroxyethyl (meth) acrylate and hydroxyisopropyl (meth) acrylate.
These (meth) acrylic monomers may be used alone or in admixture of two or more.

[3. Other monomer components]
In the method for producing U / A resin particles of the present invention, in addition to the essential components (A) and (B), styrene and its derivatives, vinyl acetate, as long as the effects of the present invention are not impaired. Other polymerizable monomers such as vinyl monomers can also be used.

  For example, as the polymerizable monomer other than the component (B), styrene, α-methyl styrene, o-methyl styrene, m-methyl styrene, p-methyl styrene, divinyl benzene and the like are exemplified as styrene and its derivatives. Examples of vinyl monomers such as vinyl acetate and other vinyl monomers include vinyl esters such as vinyl acetate and vinyl propionate, vinyl halide compounds such as vinyl chloride, polymerizable nitriles such as acrylonitrile, diallyl phthalate, Examples include triallyl isocyanurate and other polyfunctional polymerizable double bond-containing monomers.

[4. Mixture of component (A) and component (B)]
The component (A) and the component (B) are added / dispersed in the aqueous medium containing the component (C). These may be added in a mixture in which both are mixed in advance, or added separately. May be. In order to obtain a more uniform product, it is preferable to add and disperse a mixture obtained by mixing both in advance.
In addition, when (A) component is obtained as an aqueous dispersion, the mixture of (A) component and (B) component is obtained as a mixed liquid (or mixed dispersion).

  As a method of obtaining a mixture obtained by mixing the two, the method of mixing the component (B) with the component (A) obtained after the formation reaction of the urethane polymer as the component (A), or the component (B) In the presence of the constituent component (meth) acrylic monomer, a method in which a polyisocyanate compound and a diol compound are urethanated to produce a component (A) to obtain a mixture of both is preferably used.

  In particular, when the latter method is used, the resulting fine particles are more preferable because the (A) component and the (B) component are particles that are more closely combined. In particular, when the component (B) contains a urethane-binding polymerizable monomer such as the hydroxyl group-containing (meth) acrylic monomer as at least a part thereof, the hydroxyl group reacts with the polyvalent isocyanate. The polymerizable double bond is contained in the component (A), and when the (meth) acrylic monomer is polymerized, the polymerizable double bond is converted into the (meth) acrylic single component of the component (B). The component (A) and the component (B) react with the monomer and can be more closely combined, which is particularly preferable.

  The mixing ratio of the component (A) and the component (B) is preferably a weight ratio of (A) / (B) = 80/20 or less, preferably 70/30 or less. If it is greater than 80/20, fine particles may be difficult to be formed. On the other hand, the lower limit of the mixing ratio is preferably 20/80, and preferably 30/70. If it is less than 20/80, stickiness may easily occur.

[5. (C) component (dispersion stabilizer)]
As the dispersion stabilizer of component (C), a dispersion stabilizer usually used for forming an oil-in-water dispersion can be used without any particular limitation. Specific examples thereof include so-called polyvinyl alcohols (hereinafter referred to as “PVA”) such as partially saponified polyvinyl acetate and fully saponified polyvinyl acetate (polyvinyl alcohol), cellulose derivatives such as hydroxypropylmethylcellulose, gelatin and the like. And water-soluble polymers.

  Further, anionic surfactants such as sodium lauryl sulfate and sodium dodecylbenzene sulfonate, nonionic surfactants such as sorbitan fatty acid esters and glycerin fatty acid esters may be used as a dispersion aid. These dispersing agents or dispersing aids can be used alone or in combination of two or more.

  Examples of partially saponified polyvinyl acetate include “GOHSENOL GM-14”, “GH-17”, “GH-20” manufactured by Nippon Synthetic Chemical Industry Co., Ltd., “Kuraray Poval PVA217” manufactured by Kuraray Co., Ltd. (Trade name, the same shall apply hereinafter), “same PVA220”, “Denkapoval B-17”, “same B-20” manufactured by Denki Kagaku Kogyo Co., Ltd. and the like.

  Examples of fully saponified polyvinyl acetate (polyvinyl alcohol) include “GOHSENOL NM-14”, “NH-18”, “NH-26” manufactured by Nippon Synthetic Chemical Industry Co., Ltd., and Kuraray Co., Ltd. Examples thereof include “Kuraray Poval PVA117” and “PVA110”, “Denkapoval K-17E” and “K-24E” manufactured by Denki Kagaku Kogyo Co., Ltd.

  This component (C) is used by dissolving or dispersing in an aqueous medium. Examples of the aqueous medium include water or a mixed solvent of water and water-soluble water alcohol (methanol, ethanol, etc.).

  The proportion of the component (C) used is preferably 1% by weight or more and preferably 2% by weight or more with respect to the total solid content of the components (A) and (B). If it is less than 1% by weight, the effect of stably dispersing the produced particles in the aqueous medium is insufficient, and coarse particles may be produced, or the particles may be separated and settled. On the other hand, the upper limit of the use ratio is preferably 20% by weight, and preferably 15% by weight. If it is more than 20% by weight, the average particle size of the obtained U / A resin particles tends to be less than the range described later, the generation of fine particles increases, and separation from an aqueous medium by filtration becomes difficult. It may take a long time.

[6. Component (D) (polymerization initiator) and other additives]
As the polymerization initiator of component (D), a polymerization initiator used in normal radical polymerization can be used without any particular limitation. Examples of this radical polymerization initiator include persulfates such as ammonium persulfate, potassium persulfate, and sodium persulfate, 2,2′-azobisisobutyronitrile, 2,2′-azobis (2,4-dimethyl). Radical polymerization initiators such as azo compounds such as valeronitrile), hydroperoxides such as hydrogen peroxide and t-butyl hydroperoxide, peroxides such as benzoyl peroxide and lauroyl peroxide, and the like. Or a mixture of two or more. In addition, redox polymerization is initiated by using these radical polymerization initiators in combination with a reducing agent such as sodium sulfite, sodium hydrogen sulfite, sodium thiosulfate, tartaric acid, L-ascorbic acid, sodium formaldehyde sulfoxylate (Longalite), etc. It can also be used as an agent.
The amount of the component (D) used may be an amount generally used for normal radical polymerization such as 0.01 to 2% by weight with respect to the (meth) acrylic monomer.

  Furthermore, in the method of the present invention, if necessary, a polymerization degree adjusting agent (chain transfer agent, cross-linking agent), antioxidant, pH adjusting agent, redox type used for polymerization of (meth) acrylic monomers. Various polymerization assistants such as an initiator activator can be added as appropriate, and the amount and conditions of use of each of these components are generally implemented by polymerization of (meth) acrylic monomers. There is no problem with the appropriate amount and conditions. For example, the polymerization degree adjusting agent is 0.01 to 5% by weight with respect to the (meth) acrylic monomer, the antioxidant is 0.01 to 5% by weight with respect to the U / A resin, and the pH adjusting agent is U. About 0.5-1.5 equivalents of alkaline substances such as ammonia and sodium hydroxide may be used as needed for the acid component used in the / A resin.

  Examples of the polymerization degree modifier usable in the method of the present invention include chain transfer agents such as trichloroethylene, carbon tetrachloride, 2-mercaptoethanol, octyl mercaptan, diallyl phthalate, triallyl isocyanurate, ethylene glycol diacrylate, Examples of the crosslinking agent include methylolpropane trimethacrylate.

[7. Radical polymerization reaction]
As described above, in the radical polymerization reaction, a mixture of the component (A) and the component (B) is added and dispersed in an aqueous medium containing the component (C), and then the component (D) is used using the component (D). This is done by polymerizing the components. Thereby, U / A resin aqueous suspension is obtained.

  The polymerization temperature of this radical polymerization reaction is usually about 50 to 100 ° C., and the reaction time is usually about 2 to 16 hours, preferably about 3 to 10 hours. The pressure condition is preferably set so that a liquid component in the reaction system, for example, a diol or a (meth) acrylic monomer is refluxed in accordance with the reaction temperature.

Since the obtained U / A resin aqueous suspension has a particle size larger than that obtained by the conventional method, the U / A resin particles and the aqueous medium can be separated by filtration. .
The average particle size of the obtained U / A resin particles is preferably 5 μm or more, more preferably 10 μm or more, particularly preferably 15 μm or more, and particularly preferably 20 μm or more. If the average particle size is smaller than 5 μm, it may take time to separate the obtained fine particles. On the other hand, the upper limit of the average particle diameter is preferably 250 μm, more preferably 200 μm, particularly preferably 150 μm, and particularly preferably 100 μm. If the average particle size is larger than 250 μm, there may be a problem that separation / sedimentation is likely to occur in the production process.
In addition, as a measuring method of particle diameter, the method of observing with an optical microscope, the method of measuring using a laser diffraction type particle diameter measuring machine, a light scattering type particle diameter measuring machine, etc. are mentioned.

[8. Application]
The U / A resin particles produced in this way can be applied with a simpler processing method for applications such as coating agents and cosmetics by making use of the film forming ability.

  EXAMPLES Hereinafter, although this invention is demonstrated in detail using an Example, this invention is not limited by a following example, unless the summary is exceeded. First, the raw materials used will be described.

(raw materials)
[Raw material of component (A)]
P-2010: methylpentanediol adipate, manufactured by Kuraray Co., Ltd .: P-2010, hydroxyl value (OHV): 57
Bis-MPA: dimethylolpropionic acid, manufactured by Guangei Perstorp: Bis-MPA
IPDI: Isophorone diisocyanate, manufactured by Evonik Degussa Japan Co., Ltd .: IPDI

[Component (B)]
・ MMA ... Methyl methacrylate, manufactured by Mitsubishi Rayon Co., Ltd. ・ BA ... Butyl acrylate, manufactured by Mitsubishi Chemical Corporation

[Component (C)]
-PVA205: polyvinyl alcohol, manufactured by Kuraray Co., Ltd .: PVA205, 10 wt% aqueous solution [component (D)]
H-70 t-butyl hydroperoxide, manufactured by Kayaku Akzo Co., Ltd .: Kayabutyl H-70
・ Ascorbic acid: BASF Japan

[Example 1]
To a four-necked flask equipped with a thermometer, a stirrer and a reflux condenser, add 60 parts by weight of P-2010, 9.4 parts by weight of Bis-MPA, 70 parts by weight of MMA, and 39 parts by weight of BA, and stir. And the temperature increase was started. When the internal temperature reached 50 ° C., 40 parts by weight of IPDI was added, the temperature was raised to 90 ° C., and then maintained at 90 ° C. to conduct a urethanization reaction for 5 hours, and the urethane polymer and the (meth) acrylic monomer A mixture with was obtained. (At this time, the weight ratio of (A) urethane polymer / (B) (meth) acrylic monomer was 50/50.)
To a four-necked flask equipped with a separately prepared thermometer, stirrer and reflux condenser, add 70 parts by weight of a 5% by weight aqueous solution of PVA205 and 630 parts by weight of ion-exchanged water, and then heat to 60 ° C. and stir. Started.
Here, 0.3 parts by weight of H-70 and 0.1 parts by weight of ascorbic acid were added, and while adjusting the liquid temperature to 60 ° C., the urethane polymer and the (meth) acrylic monomer obtained above were Was added over 3 hours using a dropping funnel. Stirring was continued after completion of the addition, and after the heat generation due to the polymerization was completed, stirring was continued for 30 minutes while maintaining the internal temperature at 50 ° C. to obtain urethane / (meth) acrylic composite resin particles.
After cooling, urethane / (meth) acrylic composite resin particles were collected using a 200-mesh filter cloth. The obtained composite resin particles were washed with ion-exchanged water until the washing solution did not become cloudy.
The charge amount and conditions are shown in Table 1.

[Example 2]
As shown in Table 1, urethane / (meth) acrylic composite resin particles were produced in the same manner as in Example 1 except that the use ratio of the (meth) acrylic monomer was changed.
The charge amount and conditions are also shown in Table 1.

(result)
The fine particles obtained in Examples 1 and 2 were observed with an optical microscope. The observation results are shown in FIGS. 1 and 2, respectively.
On each figure, 10 of the observed particles were randomly selected and the particle size was measured. The average value of the measured particle diameters was calculated as the average particle diameter. The results are shown in Table 2.
From the above results, by using the method of the present invention, urethane-acrylic composite particles (average particle diameter of 130 nm) as shown in Example 1 of Patent Document 1 (Japanese Patent Laid-Open No. 11-14149) (the same document, [0093] It can be seen that urethane- (meth) acrylic composite resin particles having a particle diameter of about 1000 times that of the composite resin particles can be obtained.

Claims (4)

It was obtained by reacting a carboxyl group-containing diol with a polyvalent isocyanate compound in the presence of the component (B) that is a (meth) acrylic monomer to produce a component (A) that is a urethane polymer. , the (a) mixture of the the component (B) component, a dispersion stabilizer (C) is added to and dispersed in an aqueous medium containing a component,
Subsequently, the said (B) component is polymerized using (D) component which is a polymerization initiator, The manufacturing method of a urethane / (meth) acrylic-type composite resin particle characterized by the above-mentioned. The method for producing urethane / (meth) acrylic composite resin particles according to claim 1 , wherein at least a part of the carboxyl group of the component (A) is neutralized with a basic compound. (A) component which is a urethane polymer and (B) component which is a (meth) acrylic monomer at a weight ratio of (A) / (B) = 80/20 to 20/80, with a dispersion stabilizer Add and disperse in an aqueous medium containing a component (C),
Using partially saponified polyvinyl acetate as the component (C),
Subsequently, the said (B) component is polymerized using (D) component which is a polymerization initiator, The manufacturing method of a urethane / (meth) acrylic-type composite resin particle characterized by the above-mentioned. The urethane / (meth) acrylic composite resin according to any one of claims 1 to 3 , wherein a particle diameter of the urethane / (meth) acrylic composite resin particles is 5 to 250 µm. Particle production method.